Process for spinning dye-resistant copolyamide filaments

ABSTRACT

A terpolyamide, formed from reactants polymerized in the presence of the equivalent of at least 3.0 mole percent of a monofunctional acid or basic stabilizer, is melt spun into filaments which are subsequently cold drawn.

United States Patent [72] inventors Owen BurchellEdgar Priority Blackley, Manchester;

Michael Richard Yates, Horsforth, near Leeds, both of England Sept. 13, 1966 Nov. 16, 1971 Imperial Chemical industries Limited London, England Sept. 16, 1965 Great Britain PROCESS FOR SPINNING DYE-RESISTANT COPOLYAMIDE FILAMENTS 4 Claims, No Drawings US. Cl

Int. Cl

Field of Search References Cited UNITED STATES PATENTS 10/1969 Carter et a1 Bulletin of the Oyonite Chemical Co., Bulletin No. 10 (revised Apr. 22, 1955), US. Pat. Office Scientific Library, received Nov. 27, 1957, composed of a total of 63 pages; 4 pages, excerpts.

Primary Examiner-Jay H. Woo A!t0rney-Cushman, Darby & Cushman ABSTRACT: A terpolyamide, formed from reactants polymerized in the presence of the equivalent of at least 3.0 mole percent of a monofunctional acid or basic stabilizer, is melt spun into filaments which are subsequently cold drawn.

PROCESS FOR SPINNING DYE-RESISTANT COPOLYAMIDE ILAMENTS The present invention is concerned with filaments formed from copolyamides which resist dyeing by acid or basic dyestufis.

Polyamide yarns, and fabrics made therefrom, are normally dyed with disperse or acid dyestuffs, basic dyestuffs being seldom used at present. in some end uses it is desirable that not all of the yarns employed should be dyed to the same extent by one of the above classes of dyestuffs, so that in piece dyeing, for example, contrast dyeing and other effects may be obtained. In order to achieve these effects some polyamide yarns are modified, e.g., chemically. in order to resist dyeing by, usually, acid dyestuffs. Such yarns are known as dye-resist yams. it is of course important that the modifications made to the yarns should in no way impair their desirable characteristics, and that physical properties of the different yarns should be as nearly as possible identical.

in a copending application for Letters Pat. No. 39587/65 we have disclosed that certain copolyamides may be prepared which, while having substantially the same softening points as polyhexamethylene adipamide have considerably higher melt viscosities at the same, or nearly the same molecular weights.

The copolyamides referred to are ternary copolymers of polyhexamethylene adipamide and polyhexamethylene terephthalamide together with a minor proportion of a third component such as polyhexamethylene isophthalamide or polyepsilon caprolactam.

We have now found that the molecular weight of these ternary copolyamides can be decreased by the addition of relatively large amounts of a molecular weight stabilizer, for example an acid, without reducing the melt viscosities thereof to levels at which they cannot be melt spun as would normally be the case. The filaments obtained from copolyamides prepared in the presence of a relatively large amount of an acid stabilizer by the normal processes of melt spinning and drawing are resistant to acid dyeing. Use of correspondingly large amounts of a basic stabilizer would of course, render the yarns resistant to basic dyeing. Such filaments would, of course, also be useful in deep dye filaments since the large number of amine end groups available as a result of the addition of a basic stabilizer would make the filaments particularly suitable for acid dyeing.

Accordingly therefore the present invention provides a process for the manufacture of polyamide filaments by melt spinning and subsequently cold drawing a copolyamide having a melt viscosity of at least 400 poisis at 290 C, wherein said copolyamide comprises at least 50 percent by weight of polyhexamethylene adipamide together with 20 percent to 40 percent by weight of polyhexamethylene terephthalate and from 2 to 20 percent by weight of a third polyamide and is formed by the polymerization of a mixture of hexamethylene diammonium adipate, hexamethylene diammonium terephthalate and a third polyamide forming salt or lactam in the presence of the equivalent of at least 3.0 mole percent of a monofunctional acid or basic stabilizer.

It is to be understood that the expression the equivalent of at least 3.0 mole percent of a monofunctional acid or basic stabilizer" includes a difunctional stabilizer present in an amount equivalent to at least 3.0 mole percent of a monofunctional stabilizer.

By the term "stabilizer" is meant the acid or basic compound, e.g., acetic acid, normally added to a polyamide fonning salt to control the molecular weight thereof.

Preferably the third polyamide forming salt or lactam in the mixture constitutes 5 to ID percent thereof and is hexamethylene diammonium isophthalate or epsilon caprolactam. The stabilizer may be an acid and is preferably a dibasic acid such as adipic acid or terephthalic acid.

The process of the present invention is illustrated in the following examples which examples are in no way intended to limit the scope of the invention.

EXAMPLE I A mixed salt comprising hexamethylene diammonium adipate, hexamethylene diammonium terephthalate and caprolactam in the mole 'ratio of 60/30/10 together with 2 mole percent of terephthalic acid stabilizer was polymerized as follows.

1726.5 g. of the above mixture together with L000 g. of water was charged to an autoclave and maintained under an atmosphere of nitrogen. The temperature of the mixture was raised, with stirring to 210 C. over a period of 1 hour 40 minutes during which time the pressure rose to 250 p.s.i.g. The pressure was maintained at this level for l hour, the temperature rising to 245 C. and then reduced to 0 p.s.i.g. over a period of 1 hour with an increase in temperature to 285 C. Finally the mixture was maintained under steam at atmospheric pressure for 1 hour at 239 C. and the copolyamide then extruded into cold water. The percentage by weight ratio of the polyamide components based on the finished copolyamide was 61.7/33. l/5.2.

The properties of the resultant copolyamide are given in table I below.

TABLE 1 Properties of 6.6/6.T/6 copolyamide stabilized with 2 mole percent terephthalic acid Amine end group equivalents per 10 g. 18.7 Carboxyl end group equivalents per 10' g. 183.5 Melt viscosity 385 poises at 300 C.

TABLE II Properties of drawn 66/6.T/6 copolyamide yarn drawn denier 9B.l

Tenacity (g/d) 4.57 Extension to break (5) 2L5 Initial Modulus (g/d/l00% Ext.) 22.0 Boiling water shrinkage (56) I6 Amine end group equivalents per lo g. l2.5

Carboxyl end group equivalents per l0 g. 166.]

The yarn was knitted on a circular stocking machine together with a 66 nylon control and the fabric was dyed with Solway Blue B. A distinct shade difference was visible between the panels and after overdyeing with Dispersal fast Yellow A the panel containing the copolymer yarn was yellow and the 66 nylon control panel green.

EXAMPLES ll & lll

Mixed salts containing hexamethylene diammonium adipate, hexamethylene diammonium terephthalate and caprolactam in the mole ratio 60/30/l0 together with water and 1.8 and 2.5 mole percent of adipic acid stabilizer respectively were polymerized by the method described with reference to example I.

The properties of the copolyamides formed are given in table 2 below.

TABLE II II III Amine end group equivalents per l 5. l9 l5 Carboxyl end group equivalents per l0 g. l73.0 Z29 Melt viscosity L200 poise: L300 at 290 C. at 290 C.

Filaments spun from the copolymers were resistant to acid dyeing.

EXAMPLE IV TABLE 3 Properties of 6.6/6T/6 copolyamide stabilized with 2 mole percent of hexamethylene diamine 16 .1045 noises an Amine end group equivalents per l0 3. Carboxyl end group equivalents per l0 g. Melt viltcoulty Filaments spun from the copolymer were resistant to basic dyestuffs, but dyed well with acid dyes.

What we claim is:

l. A process for the manufacture of drawn terpolyamide filaments comprising melt spinning into filaments terpolyamide having a melt viscosity of at least 400 poises at 290C. and formed by the polymerization of a mixture of hexamethylene diammonium adipate, hexamethylene diammonium terephthalate and a third polyamide forming member selected from the group consisting of hexamethylene diammonium isophthalate and epsilon caprolactam in the presence of the equivalent of at least 3.0 mole percent of a monofunctional acid or basic stabilizer, and subsequently cold drawing the said filaments.

2. A process according to claim 1 wherein the stabilizer is adipic acid or terephthalic acid.

3. A process according to claim 1 wherein the stabilizer is hexamethylene diamine.

4 A process according to claim 1 wherein the third polyamide forming member is present in amounts of 5 to l0 percent by weight of said mixture.

I I i i I! 

2. A process according to claim 1 wherein the stabilizer is adipic acid or terephthalic acid.
 3. A process according to claim 1 wherein the stabilizer is hexamethylene diamine.
 4. A process according to claim 1 wherein the third polyamide forming member is present in amounts of 5 to 10 percent by weight of said mixture. 